NTP
                           NTP 297-1001-100                  PAGE 14
                          PREL., ISSUE 01D03
                               79 09 21



  5.   SOFTWARE SYSTEM DESCRIPTION


  5.01   The  DMS software  system is  designed for  flexibility and
  efficiency.    It  includes  all the  programs  necessary  for  an
  operational system.  Included in the  software are call processing
  programs,  administrative  programs,   maintenance  programs,  and
  operating system programs.

  5.02   The basic logical building block of the DMS software system
  is the  module.  Each  module contains the  program code  and data
  necessary  for  carrying  out a  specific  telephony  function  or
  sequence.  The flexibility  of  the  software system  is  achieved
  through  the  organization  of the  system  into  many  separately
  compilable modules.  In addition, provision is made for a group of
  optional  modules  containing  the code  and  data  necessary  for
  implementing feature-dependent  functions.  An  appropriate subset
  of these modules can be chosen to engineer a particular office.

  5.03   The basic language for the  DMS system is PROTEL (PRocedure
  Oriented Type Enforcing  Language).  It is a   high level language
  designed  for use  in  switching  systems.  PROTEL  contains  many
  features which  facilitate the  implementation of  a reliable  and
  maintainable software system.
































                  DMS-100 FAMILY SYSTEM DESCRIPTION
                  (c) NORTHERN TELECOM LIMITED, 1978